Welcome to Demon School! Iruma-Kun 7 (manga)

After Iruma makes an offhand comment about wanting to understand demons better, his trusty magical ring casts a sneaky spell to make it easier. The only problem? It’s turned the normally happy-go-(un)lucky Iruma into the devilishly dark Irumean! This spicy Iruma soon stirs up the Misfit Class and leads them into a crusade to claim the biggest prize on campus: the lost Demon King’s personal classroom, the Royal One!